Evidence that masks can help control the spread of the new coronavirus that causes COVID-19 has grown since the virus first emerged, extending life around the world. In March, we outlined the growing research on the effectiveness of masks and explained why experts support their use.
But a persistent string of misinformation falsely claiming that masks don’t work and are actually dangerous, have continued to be recycled and shared for more than a year, fueling the pandemic.
Internet headlines in recent days have falsely reported that a “Stanford study” has proven that masks are ineffective and dangerous. In fact, the article in question is hypothetical by one author and does not come from anyone currently affiliated with the university.
“Stanford study results: Face masks do not prevent COVID-19 transmission and may actually cause health impairment and premature death,” reads an April 19 headline from Gateway Pundit, a site conservative web is notorious for spreading misinformation. The story – shared on Facebook nearly 28,000 times, according to CrowdTangle analytics data – cites another website, NOQ reports, whose story was published two days earlier.
Similarly, the American Conservative Movement’s website also ran the headline, “Stanford study quietly published at NIH.gov proves that masks are completely worthless against Covid.” It has been shared on Facebook more than 10,000 times.
The article being referenced is not an original “research”, but one person’s hypothesis – or suggested explanation – based on a review of several prior literature. It was first published online in November by the magazine Medical theory, which describes itself as “a forum for ideas in medicine and related biomedical sciences”. While the article appeared on PubMed Central – an archive of scientific literature run by National Institutes of Health’s National Library of Medicine – that doesn’t indicate the NIH endorses or agrees with the content, as some of the stories about the virus suggest it is wrong.
The author of the article, Baruch Vaishelboim, is listed as affiliated with the “Department of Cardiology, Palo Alto Veterans Health Care System / Stanford University, Palo Alto, CA, USA.”
But Julie Greicius, spokesperson for Stanford Healthcare, and the university’s School of Medicine, told us in an email that “[t]Author affiliation is incorrectly attributed to Stanford, and we have requested a correction” from the author and the journal.
“The author, Baruch Vaishelboim, has no affiliation with VA Palo Alto or Stanford Health Systems at the time of publication and has not had any affiliation since 2016, when his one-year tenure as as a visiting scholar on matters unrelated to this paper ends,” she said in an email. She also noted that “Stanford Medicine strongly advocates the use of masks to control the spread of COVID-19.”
Spokesperson for VA Palo Alto Healthcare System, Michael Hill-Jackson, also told us in an email that “Baruch Vaishelboim does not work for VA and is incorrectly linked on this site. ” He said Vaishelboim “was a postdoc assistant to one of our researchers from 2015-2016, however, he was never formally employed by the VA and his time in this role was complete. Completely unrelated to this article.
So no, the paper is not a Stanford study, as the title claims. It is not clear where Vaishelboim is currently working or why the article makes the incorrect alignment. We have sent him several questions but have yet to receive a response.
We contacted the editor of Medical theory, Mehar Manku, about Vaishelboim’s article and he said in an email that the journal was aware of “issues related to the publication in question” and that “[a]actions are in progress. “
Update, May 3: At Manku’s request, Elsevier, publisher of Medical Hypotheses, retracted Vaishelboim’s paper and apologized to readers “for the difficulties this problem has caused”. The retraction, in part, reads:
The Editorial Board concludes that the author’s hypothesis is false on the following grounds:
1. A broader review of the available scientific evidence clearly shows that an approved respirator with appropriate certification, and worn according to instructions, is an effective means of preventing transmission of COVID-19.
2. Manuscripts misquote and selectively cite published articles. References #16, 17, 25 and 26 are all misquoted.
3. Table 1. Physiological and psychological effects of wearing masks and possible consequences on their health, created by the author. All data in the table are unverified and some statements are speculative.
4. The author submitted that he is currently affiliated with Stanford University, and the VA Palo Alto Health Care System. However, both institutes confirmed that Dr Vaishelboim ended his relationship with them in 2016.
In the paper, Vaishelboim put forward a hypothesis against the use of masks and concluded that they are “not effective for preventing human-to-human transmission of such infectious diseases and viruses.” [as] SARS-CoV-2 and COVID-19. ” It stated at one point, “DDue to the size difference between the SARS-CoV-2 diameter and the thread diameter of the mask (the virus is 1000 times smaller), SARS-CoV-2 can easily pass through any mask. ”
J. Alex Huffman, an aerosol scientist at the University of Denver, told us in a phone interview that the article reflects a fundamental lack of understanding about respiratory aerosols.
“Viruses don’t come out of your mouth like a naked virus,” he said. “They come out as liquid droplets containing mostly water but also some proteins and salts” – and if someone gets sick, viruses.
Huffman added in an email that “there is a wide distribution of particle sizes emitted when humans breathe, speak, sing or cough, but range from tens of nanometers to hundreds of micrometers. Most of these, even after evaporation, are easily removed by good masks.”
Indeed, laboratory studies have shown that masksa mass fraction of exhaled respiratory droplets, thought to be main way virus spread. Such studies have limitations, but they continue to show that masks – especially those with multiple layers and tight fit – can play a role in stopping the spread of COVID- 19.
For example, a study by scientists at the National Institutes of Disease Control and Prevention’s National Institute for Occupational Safety and Health’s Center for Occupational Health and Safety tested a variety of face coverings for their ability to prevent the spread of outside of particles from a simulated cough. N95 respirators have the best performance – blocking 99% of particles – while medical masks block 59% and three-layer cloth masks block 51%. (A face shield, on the other hand, only stops at 2%.)
And men another test, researchers in Japan evaluated how different the masks on two mannequins facing each other reduced exposure to the coronavirus. One dummy was connected to a nebulizer that made a simulated cough, “imitating a virus spreader,” and the other was connected to an artificial ventilator to simulate breathing. If both mannequins wear cotton masks or surgical masks, the chance of transmission is reduced by 60% to 70%.
For more information on the research surrounding masks, check out our SciCheck story “Evolving Science of Masks and COVID-19.”
Vaishelboim’s The paper also claims that the mask “restricting breathing, causing hypoxemia and hypercapnia”. Hypoxemia is the term for insufficient oxygen in the blood; Hypercoaemia is the presence of too much carbon dioxide in the blood.
Experts have repeatedly refuted that claim, and we’ve previously dealt with unfounded claims that masks cause unsafe oxygen levels.
Mayo Clinic notes: “For many years, health care providers have worn face masks for extended periods with no adverse health effects. “CDC recommends wearing a cloth mask when in public, and this option is very breathable. There is no risk of hypoxia, i.e. lower oxygen levels, in healthy adults. The carbon dioxide will freely diffuse through your mask as you breathe. “
The American Lung Association also notes: “We wear masks all day in the hospital. The masks are designed to be breathable and there is no evidence that low oxygen levels occur.” (However, it is recommended that people with pre-existing lung conditions contact their doctor before wearing an N95 respirator.)
Editor’s Note: SciCheck’s COVID-19 Immunization Project was made possible through a grant from the Robert Wood Johnson Foundation. The organization does not control our editorial decisions and the views expressed in our articles do not necessarily reflect those of the organization. The goal of the project is to increase exposure to accurate information about COVID-19 and vaccines, while reducing the impact of misinformation.
Frodl, Kimberly. “Breaking the myths about masks.” Mayo Clinic Health System. July 10, 2020.
Greicius, Julie. Spokesperson, Stanford Health Care. Send an email to FactCheck.org. April 21, 2021.
“Instructions to wear a mask.” Centers for Disease Control and Prevention. Updated April 19, 2021.
Hill, David G. “From the Frontline: The Truth About Masks and COVID-19.” American Lung Association. June 18, 2020.
Hill-Jackson, Michael. Spokesperson, Veterans Affairs Palo Alto Health Care System. Send an email to FactCheck.org. April 21, 2021.
“How COVID-19 spreads.” Centers for Disease Control and Prevention. Updated October 28, 2020.
Huffman, J. Alex. Associate Professor, Department of Chemistry and Biochemistry, University of Denver. Phone interview with FactCheck.org. April 21, 2021.
Lindsley, William G., et al. “Efficacy of masks, scarves, and face shields in reducing the ejection of simulated cough-generated aerosols.” Science and Technology Aerosol. January 7, 2021.
Manku, Mehar. Editor, Medical Hypothesis. Send an email to FactCheck.org. April 22, 2021.
McDonald, Jessica. “The evolving science of masks and COVID-19.” FactCheck.org. March 2, 2021.
Ueki, Hiroshi, et al. “Effectiveness of masks in preventing airborne transmission of SARS-CoV-2.” mSphere. October 2020.
Vaishelboim, Baruch. “Masks in the COVID-19 era: A health hypothesis.” Medical theories. Uploaded online November 22, 2020.